F, hybrids and method for producing hybrids using corn inbred PHR63

ABSTRACT

According to the invention, there is provided an inbred corn line, designated PHR63. This invention thus relates to the plants and seeds of inbred corn line PHR63 and to methods for producing a corn plant produced by crossing the inbred line PHR63 with itself or with another corn plant. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHR63 with another corn line or plant and to crosses with related species.

This is a continuation of prior copending application Ser. No. 07/867,591, filed Apr. 13, 1992, now abandoned, which was a continuation of application Ser. No. 07/402,109, filed Aug. 30, 1989 and which issued as U.S. Pat. No. 5,159,132 on Oct. 27, 1992.

FIELD OF THE INVENTION

This invention is in the field of corn breeding, specifically relating to an inbred corn line designated PHR63.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine in a single variety/hybrid various desirable traits. For field crops, these traits may include resistance to diseases and insects, tolerance to heat and drought, reducing the time to crop maturity, greater yield, and better agronomic quality. With mechanical harvesting of many crops, uniformity of plant characteristics such as germination and stand establishment, growth rate, maturity, and fruit size, is important.

Field crops are bred through techniques that take advantage of the plant's method of pollination. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant. A plant is cross-pollinated if the pollen comes from a flower on a different plant.

Plants that have been self-pollinated and selected for type for many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny. A cross between two homozygous lines produce a uniform population of hybrid plants that may be heterozygous for many gene loci. A cross of two plants each heterozygous at a number of gene loci will produce a population of hybrid plants that differ genetically and will not be uniform.

Corn plants (Zea mays L.) can be bred by both self-pollination and cross-pollination techniques. Corn has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the incipient ears.

The development of corn hybrids requires the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Pedigree breeding and recurrent selection breeding methods are used to develop inbred lines from breeding populations. Breeding programs combine the genetic backgrounds from two or more inbred lines or various other broad-based sources into breeding pools from which new inbred lines are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred lines and the hybrids from these crosses are evaluated to determine which of those have commercial potential.

Pedigree breeding for single-gene traits starts with the crossing of two genotypes, each of which may have one or more desirable characteristics that is lacking in the other or which complement the other. If the two original parents do not provide all of the desired characteristics, other sources can be included in the breeding population. In the pedigree method, superior plants are selfed and selected in successive generations. In the succeeding generations the heterozygous condition gives way to homogeneous lines as a result of self-pollination and selection. Typically in the pedigree method of breeding five or more generations of selfing and selection is practiced: F₁ →F₂ ; F₂ →F₃ ; F₃ →F₄ ; F₄ →F₅, etc.

Backcrossing can be used to improve an inbred line. Backcrossing transfers a specific desirable trait from one inbred or source to an inbred that lacks that trait. This can be accomplished for example by first crossing a superior inbred (A) (recurrent parent) to a donor inbred (nonrecurrent parent), which carries the appropriate gene(s) for the trait in question. The progeny of this cross is then mated back to the superior recurrent parent (A) followed by selection in the resultant progeny for the desired trait to be transferred from the non-recurrent parent. After five or more backcross generations with selection for the desired trait, the progeny will be heterozygous for loci controlling the characteristic being transferred, but will be like the superior parent for most or almost all other genes. The last backcross generation would be selfed to give pure breeding progeny for the gene(s) being transferred.

A single cross hybrid corn variety is the cross of two inbred lines, each of which has a genotype which complements the genotype of the other. The hybrid progeny of the first generation is designated F₁. In the development of hybrids only the F₁ hybrid plants are sought. Preferred F₁ hybrids are more vigorous than theist inbred parents. This hybrid vigor, or heterosis, can be manifested in many polygenic traits, including increased vegetative growth and increased yield.

The development of a hybrid corn variety involves three steps: (1) the selection of plants from various germplasm pools; (2) the selling of the selected plants for several generations to produce a series of inbred lines, which, although different from each other, each breed true and are highly uniform; and (3) crossing the selected inbred lines with unrelated inbred lines to produce the hybrid progeny (F₁). During the inbreeding process in corn, the vigor of the lines decreases. Vigor is restored when two unrelated inbred lines are crossed to produce the hybrid progeny (F₁). An important consequence of the homozygosity and homogeneity of the inbred lines is that the hybrid between any two inbreds will always be the same. Once the inbreds that give a superior hybrid have been identified, the hybrid seed can be reproduced indefinitely as long as the homogeneity of the inbred parents is maintained.

A single cross hybrid is produced when two inbred lines are crossed to produce the F₁ progeny. A double cross hybrid is produced from four inbred lines crossed in pairs (A×B and C×D) and then the two F₁ hybrids are crossed again (A×B)×(C×D). Much of the hybrid vigor exhibited by F1 hybrids is lost in the next generation (F₂). Consequently, seed from hybrid varieties is not used for planting stock.

Corn is an important and valuable field crop. Thus, a continuing goal of plant breeders is to develop high-yielding corn hybrids that are agronomically sound based on stable inbred lines. The reasons for this goal are obvious: to maximize the amount of grain produced with the inputs used and minimize susceptibility to environmental stresses. To accomplish this goal, the corn breeder must select and develop superior inbred parental lines for producing hybrids. This requires identification and selection of genetically unique individuals which in a segregating population occur as the result of a combination of crossover events plus the independent assortment of specific combinations of alleles at many gene loci which results in specific genotypes. Based on the number of segregating genes, the frequency of occurrence of an individual with a specific genotype is less than 1 in 10,000. Thus, even if the entire genotype of the parents has been characterized and the desired genotype is known, only a few if any individuals having the desired genotype may be found in a large F₂ or S₀ population. Typically, however, the genotype of neither the parents nor the desired genotype is known in any detail.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line, designated PHR63. This invention thus relates to the seeds of inbred corn line PHR63, to the plants of inbred corn line PHR63, and to methods for producing a corn plant produced by crossing the inbred line PHR63 with itself or another corn line. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHR63 with another corn line or a related species.

DEFINITIONS

In the description and examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided:

BAR PLT=BARREN PLANTS. This is the number of plants per plot that were not barren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Actual yield of the grain at harvest adjusted to 15.5% moisture. ABS is in absolute terms and % MN is percent of the mean for the experiments in which the inbred or hybrid was grown.

CLD TST=COLD TEST. This is the percentage of kernels that germinate under cold soil conditions. ABS=absolute measurement and % MN is percentage of mean of the experiments in which inbred or hybrid was grown.

COB SC=COB SCORE. The cob score is a rating of how well the grain is shelled off the cob and how badly the cob is broken up going through the combine. This is given as a 1 to 9 score with 9 being very good. A high score indicates that the grain shells off of the cob well, and the cob does not break.

DRP EAR=DROPPED EARS. This is a measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to the top developed ear node attachment and is measured in inches.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on a per plot basis for the inbred or hybrid.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred line or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barget Method, where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimum temperature used is 50° F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for an inbred line or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GRN QUL=GRAIN QUALITY. This is a 1 to 9 rating for the general quality of the shelled grain as it is harvested based on such factors as the color of the harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain quality.

KER LB=KERNELS PER POUND. This is the number of kernels per 0.1 pound.

KSZ L=KERNEL SIZE LARGE. Percentage by weight of shelled corn that passes through a screen with 25/64 inch diameter openings but does not pass through a screen with 22/64 inch diameter openings.

KSZ MF=KERNEL SIZE MEDIUM FLAT. Percentage by weight of shelled corn that passes through a screen with 22/64 inch diameter openings and a screen with 13/64 inch wide slot screen but does not pass through a screen with 18.5/64 inch diameter openings.

KSZ MR=KERNEL SIZE MEDIUM ROUND. Percentage by weight of shelled corn that passes through a screen with 22/64 inch diameter openings but does not pass through a 13/64 inch wide slot screen or a screen with 18.5/64 inch diameter openings.

KSZ S=KERNEL SIZE SMALL. Percentage by weight of shelled corn that passes through a screen with 18.5/64 inch diameter openings but does not pass through a screen with 16/64 inch diameter openings.

KSZ TIP=KERNEL SIZE TIPS. Percentage by weight of shelled corn that passes through a screen with 16/64 inch diameter openings.

KSZ XL=KERNEL SIZE EXTRA LARGE. Percentage by weight of shelled corn that does not pass through a screen with 25/64 inch diameter openings.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in inches.

POL WT=POLLEN WEIGHT. This is the weight of pollen per 100 plants taken on a plot basis. ABS refers to data in absolute, and % MN refers to data presented as percentage of experimental mean.

PRM=PREDICTED RM. This trait, predicted relative maturity (RM), is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is referred to as the Minnesota Relative Maturity Rating System.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis at an approximately 30° angle or greater would be counted as root lodged.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A corn breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

STA GRN=STAY GREEN. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STA CNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STK LDG=STALK LODGING. This is the percentage of plants that did not stalk lodge (stalk breakage) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data is given as percentage of tillers: number of tillers per plot divided by number of plants per plot.

TST WT=TEST WEIGHT UNADJUSTED. The measure of the weight of the grain in pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain in pounds for a given volume (bushel) adjusted for percent moisture.

YLD=YIELD. It is the same as BU ACR ABS.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

CLN=Corn Lethal Necrosis (MCMV=Maize Chlorotic Mottle Virus and MDMV=Maize Dwarf Mosaic Virus): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

MDM CPX=Maize Dwarf Mosaic Complex (MDMV-Maize Dwarf Mosaic Virus & MCDV-Maize Chlorotic Dwarf Virus): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

COM SMT=Common Smut (Ustilago maydis): Percentage of plants that did not have infection.

ANT ROT=Anthracnose Stalk Rot (Colletotrichum graminicola): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

SLF BLT=Southern Leaf Blight (Bipolaris maydis, Helminthosporium maydis): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

NLF BLT=Northern Leaf Blight (Exserohilum turcicum, H. turcicum): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

HC BLT=Helminthosporium Carbonum Leaf Blight (Bipolariszeicola, H. carbonum): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

COM RST=Common Rust (Puccinia sorghi): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

SO RST=Southern Rust (Puccinia polysora): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

EYE SPT=Eyespot (Kabatiella zeae): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

STW WLT=Stewart's Wilt (Erwinia stewartii): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

GOS WLT=Goss's Wilt (Corynebacterium nebraskense): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

HD SMT=Head Smut (Spacelotheca reiliana): Percentage of plants that did not have infection.

DNY MIL=Downy Mildew (Peronosclerospora sorghi): Percentage of plants that did not have infection.

FUS EAR=Fusarium Ear Mold (Fusarium moniliforme): Percentage of plants that did not have infection.

EAR MLD=General Ear Mold: Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant. This is based on overall rating for ear mold of mature ears without determining specific mold organism, and may not be predictive for a specific ear mold.

ECB DPE=Dropped ears due to European Corn Borer (Ostrinia nubilalis): Percentage of plants that did not drop ears under second brood corn borer infestation.

ECB 2SC=European Corn Borer Second Brood (Ostrinia nubilalis): Visual rating (1-9 score) of post flowering damage due to infestation by European Corn Borer. A "1" is very susceptible and a "9" is very resistant.

ECB 1LF=European Corn Borer First Brood (Ostrinia nubilalis): Visual rating (1-9 score) of pre-flowering leaf feeding by European Corn Borer. A "1" is very susceptible and a "9" is very resistant.

ECB 2IT=European Corn Borer Second Brood Tunneling (Ostrinia nubilalis): The average inches of tunneling in the stalk due to second brood (post-flowering) European Corn Borer infestation. Determined by splitting stalks with a knife, from four internodes above the ear to the ground.

DETAILED DESCRIPTION OF THE INVENTION

Inbred Corn Line PHR63 is a yellow, dent corn inbred with superior characteristics and provides an acceptable male parental line in crosses for producing first generation F₁ corn hybrids. This inbred is adapted over the Central and Western regions of the United States. The inbred can be used to produce hybrids from approximately 123-133 relative maturity based on the Minnesota Relative Maturity Rating System for harvest moisture of grain. PHR63 could be utilized as a female parent but it is a little erratic for cold test. As a male, PHR63 had heavy pollen yield. It was 114% of the experimental mean for amount of pollen from the pollen yield test averaged over 15 locations. Under severe heat and drought stress the inbred has shown a severe reduction in pollen shed under production. However, under normal conditions it is a very good male.

The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1) that follows. Most of the data in the Variety Description Information was collected at Johnston, Iowa. The inbred has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure homozygosity and phenotypic stability. The line has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in PHR63.

Inbred corn line PHR63, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed, using techniques familiar to the agricultural arts.

                  TABLE 1                                                          ______________________________________                                         PHR63                                                                          VARIETY DESCRIPTION INFORMATION                                                ______________________________________                                         Type: Dent Region Best Adapted: Central & West                                 A.  Maturity: Averaged across marturity zones. Zone: 0                         INBRED = PHR63                                                                 Heat Unit Shed: 1480                                                           Heat Unit SIlk: 1510                                                           No. Reps: 57                                                                    ##STR1##                                                                      ______________________________________                                          *If maximum is greater than 86 degrees fahrenheit, then 86 is used and if      minimum is less than 50, then 50 is used. Heat units accumulated daily an      can not be less than 0.                                                  

B. Plant Characteristics:

Plant height (to tassel tip): 220 cm

Length of top ear internode: 13 cm

Number of ears per stalk: Single ear with slight two-ear tendency

Ear height (to base of top ear): 79 cm

Number of tillers: None

Cytoplasm type: Normal

C. Leaf:

Color: (WF9) Medium green

Angle from Stalk: 30-60 degrees

Marginal Waves: (OH7L) Many

Number of Leaves (mature plants): 19

Sheath Pubescence: (W22) Light

Longitudinal Creases: (OH56A) Few

Length (Ear node leaf): 76 cm

Width (widest point, ear node leaf): 9 cm

D. Tassel:

Number lateral branches: 8

Branch Angle from central spike: 30-40 degrees

Pollen Shed: Heavy based on pollen Yield Test (114% of experiment mean).

Peduncle Length (top leaf to basal branches): 20 cm

Anther Color: Yellow with slight red tint

Glume Color: Green

E. Ear (Husked Ear Data Except When Stated Otherwise):

Length: 16 cm

Weight: 87 gm

Mid-point Diameter: 44 mm

Silk Color: Yellowish-pink

Husk Extension (Harvest stage): Long (8-10cm beyond ear tip)

Husk Leaf: Long (>15 cm)

Taper of Ear: Slight taper

Position of Shank (dry husks): Drooping

Kernel Rows: Distinct, slightly curved, Number=16

Husk Color (fresh): Light green

Husk Color (dry): Buff

Shank Length: 17 cm

Shank (No. of internodes): 8

F. Kernel (Dried):

Size (from ear mid-point)

Length: 11 mm

Width: 8 mm

Thick: 5 mm

Shape Grade (% rounds): 20-40% medium rounds based on Parent Test.

Pericarp Color: Colorless

Aleurone Color: Homozygous yellow

Endosperm Color: Yellow

Endosperm Type: Normal

Gm Wt/100 Seeds (unsized): 28 gm

G. Cob:

Diameter at mid-point: 27 mm

Strength: Strong

Color: Reddish-pink

H. Diseases:

Corn Lethal Necrosis (MCMV=Maize Chlorotic Mottle Virus and MDMV-Maize Dwarf Mosaic Virus): Intermediate

Maize Dwarf Mosaic Complex (MDMV & MCDV=Maize Chlorotic Dwarf Virus): Susceptible

Anthracnose Stalk Rot (C. Graminicola): Intermediate

S. Leaf Blight (H. Maydis): Susceptible

N. Leaf Blight (H. Turcicum): Intermediate

Carbonum Leaf Blight (H. Carbonum): Intermediate

Common Rust (P. Sorghi): Resistant

Eye Spot (K. Zeae): Intermediate

Gray, Leaf Spot (C. Zeae): Susceptible

Stewarts Wilt (E. Stewartii): Intermediate

Goss's Wilt (C. Nebraskense): Resistant

Common Smut (U. Maydis): Resistant

Head Smut (S. Reiliana): Resistant

Downy Mildew (S. Sorghi): Resistant

Fusarium Ear Mold (F. Moniliforme): Resistant

I. Insects:

European Corn Borer-1 Leaf Damage (Pre-flowering): Intermediate

European Corn Borer-2 (Post-flowering): Susceptible

J. Variety Most Closely Resembling:

    ______________________________________                                                Character      Inbred                                                   ______________________________________                                                Maturity       PHV78                                                           Usage          PHV78                                                    ______________________________________                                    

PHV78 (PVP Certificate No. 8800003 and U.S. Pat. No. 4,812,599) is a Pioneer Hi-Bred International, Inc. proprietary inbred.

Data for items B, C, D, E, F, and G are primarily based on a maximum of three reps of data from Johnston, Iowa grown in and 1988, plus description information from the maintaining station.

                  TABLE 2                                                          ______________________________________                                         ELECTROPHORESIS RESULTS                                                        Isozyme Genotypes for PHR63                                                    Isozyme data was generated for inbred corn line PHR63                          according to the procedure described in Goodman, M. M. and                     Stuber, C. M., "Genetic identification of lines and crosses                    using isoenzyme electrophoresis," Proceedings of the Thirty-                   Fifth Annual Corn and Sorghum Industry Research Conference,                    Chicago, Illinois (1980).                                                              Alleles Present                                                                Loci  PHR63                                                            ______________________________________                                                 ACP1  4                                                                        ADH1  4                                                                        CAT3  9                                                                        DIA1  8                                                                        GOT1  4                                                                        GOT2  2                                                                        GOT3  4                                                                        IDH1  4                                                                        IDH2  6                                                                        MDH1  6                                                                        MDH2  6                                                                        MDH3  16                                                                       MDH4  12                                                                       MDH5  12                                                                       MMM   4                                                                        PGM1  9                                                                        PGM2  4                                                                        PGD1  3.8                                                                      PGD2  5                                                                        PHI1  4                                                                ______________________________________                                    

INDUSTRIAL APPLICABILITY

This invention also is directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant wherein the first or second parent corn plant is an inbred corn plant from the line PHR63. Further, both first and second parent corn plants can come from the inbred corn line PHR63. Thus, any such methods using the inbred corn line PHR63 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, and the like. All plants produced using inbred corn line PHR63 as a parent are within the scope of this invention. Advantageously, the inbred corn line is used in crosses with other, different, corn inbreds to produce first generation (F₁) corn hybrid seeds and plants with superior characteristics.

As used herein, the terms "plant and plant parts" include plant cells, plant protoplasts, plant cell tissue culture from which corn plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as embryos, pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk and the like.

Tissue culture of corn is described in European Patent Application, publication 160,390, incorporated herein by reference. Corn tissue culture procedures are also described in Green and Rhodes, "Plant Regeneration in Tissue Culture of Maize," Maize for Biological Research (Plant Molecular Biology Association, Charlottsville, Va. 1982, at 367-372. Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce the inbred line PHR63.

The utility of inbred line PHR63 also extends to crosses with other species. Commonly, suitable species will be of the family Graminaceae, and especially of the genera Zea, Tripsacum, Coix, Schlerachne, Polytoca, Chionachne, and Trilobachne, of the tribe Maydeae. Of these, Zea and Tripsacum, are most preferred. Potentially suitable for crosses with PHR63 may be the various varieties of grain sorghum, Sorghum bicolor (L.) Moench.

Corn is used as human food, livestock feed, and as raw material in industry. The food uses of corn, in addition to human consumption of corn kernels, include both products of dry- and wet-milling industries and alkaline cooking. The principal products of corn dry milling are grits, meal and flour. The corn wet-milling industry can provide corn starch, corn syrups, and dextrose for food use. Alkaline cooking provides snack foods (i.e., corn chips, tortillas, etc.) Corn oil is recovered from corn germ, which is a byproduct of both dry- and wet-milling industries.

Corn, including both grain and non-grain portions of the plant, is also used extensively as livestock feed, primarily for beef cattle, dairy cattle, hogs, and poultry.

Industrial uses of corn are mainly from corn starch from the wet-milling industry and corn flour from the dry-milling industry. The industrial applications of corn starch and flour are based on functional properties, such as viscosity, film formation, adhesive properties, and ability to suspend particles. The corn starch and flour have application in the paper and textile industries. Other industrial uses include applications in adhesives, building materials, foundry binders, laundry starches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of corn are also used in industry. Stalks and husks are made into paper and wallboard and cobs are used for fuel and to make charcoal.

The seed of inbred corn line PHR63, the plant produced from the inbred seed, the hybrid corn plant produced from the crossing of the inbred, hybrid seed, and various parts of the hybrid corn plant can be utilized for human food, livestock feed, and as a raw material in industry.

EXAMPLE INBRED AND HYBRID PERFORMANCE OF PHR63

In the examples that follow the traits and characteristics of inbred corn line PHR63 are given as a line and in hybrid combination. The data collected on inbred corn line PHR63 is presented for the key characteristics and traits.

The results in Table 3 compare PHR63 to PHV78. PHV78 (PVP Certificate #8800003, U.S. Pat. No. 4,812,599) is an important inbred that would be used in the area that PHR63 would be used and would cross well with many of the same inbred lines. The results show that the two lines differ significantly for a number of traits. PHR63 offers some key advantages over PHV78 in that it is earlier flowering but carries more harvest moisture, has a better early stand count, is much shorter, and has much harder textured grain than PHV78. PHR63 could be used as a female while PHV78 is totally unacceptable as a female. In the area of disease and insect resistance, PHR63 appears more resistant to common rust, is much better for ear mold and fusarium ear mold resistance than PHV78.

The results in table 4 compare PHR63 to PHV78 crossed to the same inbred testers. The results show that the two lines differ significantly for a number of traits in hybrid combination. PHR63 offers some key advantages over PHV78 in hybrid combination for earlier flowering, greater resistance to root lodging and better stay green. The PHR63 hybrids had much higher grain test weights, much better grain quality and better seedling vigor than the PHV78 hybrids. PHR63 hybrids are much shorter which is preferred by the grain farmer. The PHR63 hybrids have particularly better performance in the Western areas while the PHV78 hybrids have better performance in the eastern and southern areas. PHR63 has given good performance in specific hybrid combinations and one of its hybrids has performed well in food grade evaluations because of its high test weight and good grain quality. Also this hybrid has high grain yields and good root lodging resistance in the Western areas.

                                      TABLE 3                                      __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  INBRED #1 - PHR63                                                              INBRED #2 - PHV89                                                              __________________________________________________________________________                 BU BU  BAR                                                                               BRT                                                                               EAR EAR EST TIL GDU GDU GRN    PLT POL                        VAR ACR                                                                               ACR PLT                                                                               STK                                                                               HT  SZ  CNT LER SHD SLK QUL MST                                                                               HT  WT                 YEAR    #   ABS                                                                               % MN                                                                               ABS                                                                               ABS                                                                               ABS ABS ABS ABS ABS ABS ABS ABS                                                                               ABS ABS                __________________________________________________________________________     TOTAL SUM                                                                              1   76.8                                                                              105 89.6                                                                              100.0                                                                             26.6                                                                               6.4 31.0                                                                               2.1 149.1                                                                              151.3                                                                              8.0 16.5                                                                              77.3                                                                               220.7                      2   85.8                                                                              116 88.9                                                                              96.1                                                                              29.7                                                                               7.1 29.0                                                                               1.9 158.5                                                                              164.5                                                                              7.2 15.1                                                                              86.7                                                                               255.2                      LOCS                                                                               2  2   13 6  18  20  70  26  76  73  3   2  19  12                         DIFF                                                                               8.9                                                                               12  0.7                                                                               3.9                                                                               3.1 0.7 2.1 0.2 9.3 13.2                                                                               0.8 1.3                                                                               9.4 34.5                       PROB                                                                               .238                                                                              .190                                                                               .694                                                                              .127                                                                              .004#                                                                              .015+                                                                              .001#                                                                              .885                                                                               .000#                                                                              .000#                                                                              .525                                                                               .073*                                                                             .000#                                                                              .247               __________________________________________________________________________                 POL POL RT  TAS TAS TAS TEX TST SCT SDG STA STK                                                                               STK                         VAR WT  SC  LDG BLS SZ  WT  EAR WT  GRN VGR GRN CNT                                                                               LDG                 YEAR    #   % MN                                                                               ABS ABS ABS ABS ABS ABS ABS ABS ABS ABS ABS                                                                               ABS                 __________________________________________________________________________     TOTAL SUM                                                                              1   114 7.2 74.2                                                                               8.0 6.4 5.3 7.6 61.0                                                                               7.3 5.5 5.3 26.5                                                                              99.0                        2   135 6.6 72.4                                                                               9.0 7.1 6.6 4.3 56.1                                                                               5.5 5.1 5.9 25.9                                                                              98.9                        LOCS                                                                               12  42  3   3   30  12  16  2   26  30  20  59 1                           DIFF                                                                               21  0.6 1.8 1.0 0.8 1.3 3.3 4.9 1.8 0.3 0.6 0.6                                                                               0.1                         PROB                                                                               .230                                                                               .037+                                                                              .886                                                                               .423                                                                               .001#                                                                              .004#                                                                              .000#                                                                              .181                                                                               .000#                                                                              .231                                                                               .122                                                                               .201                   __________________________________________________________________________                 YLD COM COM EAR ECB                                                                               ECB ECB                                                                               FUS GLF MDM NLF                                                                               SLF                                                                               SO STW                         VAR SC  RST SMT MLD DPE                                                                               1LF 2SC                                                                               EAR SPT CPX BLT                                                                               BLT                                                                               RST                                                                               WLT                 YEAR    #   ABS ABS ABS ABS ABS                                                                               ABS ABS                                                                               ABS ABS ABS ABS                                                                               ABS                                                                               ABS                                                                               ABS                 __________________________________________________________________________     TOTAL SUM                                                                              1   6.1 8.0 0.0 7.3 56.7                                                                              6.8 3.9                                                                               59.3                                                                               2.1 3.0 3.3                                                                               4.0                                                                               5.0                                                                               7.0                         2   6.1 1.0 1.0 5.3 73.3                                                                              6.1 4.6                                                                               12.8                                                                               2.9 3.0 5.5                                                                               5.3                                                                               6.0                                                                               7.5                         LOCS                                                                               33  1   1   28  2  18  5  2   4   1   3  2  1  2                           DIFF                                                                               0.0 7.0 1.0 2.0 16.7                                                                              0.7 0.7                                                                               46.6                                                                               0.8 0.0 2.2                                                                               1.3                                                                               1.0                                                                               0.5                         PROB                                                                               .889        .000#                                                                              .344                                                                              .028+                                                                              .500                                                                              .158                                                                               .058*   .204                                                                              .500  .500                __________________________________________________________________________      *= 10% SIG                                                                     += 5% SIG                                                                      #= 1% SIG                                                                

                                      TABLE 4                                      __________________________________________________________________________     Average Inbred by Tester Performance Comparing PHR63 to                        PHV78 crossed to the same Inbred Testers and Grown in the                      Same Experiments. All Values are Expressed as percent of the                   experiment mean except Predicted RM, Selection Index, and                      Yield (Bu./Ac.).                                                               __________________________________________________________________________                      SEL BU        GDU STK RT  BAR                                        Inbred                                                                               PRM IND ACR                                                                               YLD MST                                                                               SHD LDG LDG PLT                                 __________________________________________________________________________     TOTAL  REPLIC.                                                                              317 321 333                                                                               333 333                                                                               84  301 181 105                                 MEAN WTS                                                                              PHV78 123 107 147                                                                               106 100                                                                               101 99  98  101                                 MEAN WTS                                                                              PHR63 126 104 145                                                                               104 106                                                                               99  100 101 101                                        DIFF. 3   3   2  2   6  2   0   3   1                                   __________________________________________________________________________                  STA TST COB                                                                               GRN SDG EST                                                                               PLT                                                                               EAR                                                                               DRP                                                                               BRT                                       Inbred                                                                               GRN WTA SC QUL VGR CNT                                                                               HT HT EAR                                                                               STK                                __________________________________________________________________________     TOTAL  REPLIC.                                                                              219 331 25 60  128 177                                                                               167                                                                               169                                                                               155                                   MEAN WTS                                                                              PHV78 97  98  85 92  101 100                                                                               102                                                                               101                                                                               100                                   MEAN WTS                                                                              PHR63 105 102 98 106 106 100                                                                               97 95 100                                          DIFF. 8   4   13 14  5   1  5  6  0                                     __________________________________________________________________________

A deposit of the inbred PHR63 is maintained by Pioneer Hi-Bred International, Inc., 700 Capital Square, 400 Locust Street, Des Moines, Iowa 50309 since prior to the filing date of this application. Access to these deposits will be available during the pendency of this application to the Commissioner of Patents and Trademarks and persons determined by the Commissioner to be entitled thereto upon request. Upon allowance of any claims in this application, all restrictions on availability to the public of such material will be removed by affording access to deposit of at least 2500 seeds of the inbred PHR63 with the American Type Culture Collection (ATCC), Rockville, Md. The seed deposited with the ATCC will be taken from the same deposit maintained by Pioneer Hi-Bred since prior to the filing date of this application. The deposit will be maintained in that depository, which is a public depository, for a period of 30 years, or 5 years after the last request, or for the effective life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. The ATCC deposit number for the Inbred PHR63 is 75221. 

What is claimed is:
 1. F₁ hybrid corn seed and plants therefrom produced by crossing inbred corn plant PHR63, having ATCC accession number 75221, with another corn plant that is not PHR63.
 2. A method for producing a hybrid corn seed which produces a hybrid corn plant having alleles which, when expressed, contributes to early flowering, root lodging resistance, better stay green, and high grain quality when compared to similarly adapted hybrids, comprising the steps of:(a) planting, in pollinating proximity, seed of corn inbred line PHR63, having ATCC accession number 75221, and another inbred line, not PHR63; (b) cultivating corn plants resulting from said planting, said corn plants having a male and female reproductive system; (c) inactivating the male reproductive system prior to pollination of the plants of either inbred line; (d) allowing natural cross pollinating to occur between the inbred lines; and (e) harvesting seeds produced on said inactivated plants of the inbred line. 